matchto and derivefrom

The match to and derive from tags are streamlined implementations of fetch_cell and fetch_row. They use less verbose syntax, and are therefore easier to read and write. In cases where data is to be pulled in from a spreadsheet, as in a ZIP code look-up, these are the best tools to use. These tags work as a pair. The match to tag initiates the spreadsheet reference, and derive from enables specific fields to be referenced.

Syntax

Use matchto on the question containing the value to check against a sheet. Use derivefrom to get the corresponding column from the matching matchto row. Closed-end variables utilizing derivefrom automatically build all options available in the referenced sheet, unless instructed to do otherwise. Additionally, a default value can be assigned if no math is present.

matchto

# Variable with data to check against sheet
matchto: Sheet name to match

derivefrom

Basic

# Variable to populate with given column for row matching matchto field's input
derivefrom: QID of matchto variable, Sheet column label to return

Default

Use default to specify a selection to use in case no matching items returned.

derivefrom: QID of matchto variable, Sheet column label to return {default: Default option ID here}

Options

Variables with derivefrom automatically contain all distinct options present in the sheet for the specified column. To override this default and prevent the automatic addition of options from the sheet, use the options decorator. This requires that options be specified locally, or via an optsfrom tag.

derivefrom: QID of matchto variable, Sheet column label to return {options: N}

Examples

Sheet

The following examples assume a system sheet named 'system.zip_db_dlxbus' (shown below). Examples for QSTATE and QREGION also refer to system sheets 'system.states' and 'system.rgopts', respectively.

Basic

P6. Please enter your ZIP code:<p>
type: text
match to: system.zip_db_dlxbus
datatype: zip5
maxlen: 5
size: 6

STATE. State
type: radio
derive from: QP6 StateCode
optsfrom: system.states

REGION. One of four geographic regions, defined by the U.S. Department of Commerce, Bureau of the Census.
type: text
derive from: QP6 Region

Default

STATE. State
type: radio
invisible: y
derive from: QP6 StateCode {default: 99}
optsfrom: system.states
99. State not found

Custom option text

To customize automatically generated closed-end response options, use a text decorator.

REGION. One of four geographic regions, defined by the U.S. Department of Commerce, Bureau of the Census.
type: radio
derive from: QP6 Region {text: The [id] Region}
optsfrom: system.rgopts

Options

To prevent the automatic generation of survey fields by derivefrom, use the options decorator.

REGION. One of four geographic regions, defined by the U.S. Department of Commerce, Bureau of the Census.
type: radio
derive from: QP6 Region {options: N}
1. North
2. South
3. East
4. West

Quotas

One can also use derivefrom variables as quotas.

REGION. One of four geographic regions, defined by the U.S. Department of Commerce, Bureau of the Census.
type: radio
derive from: QP6 Region {options: N}
quotas: y
1. North
2. South
3. East
4. West